First Lady Michelle Obama stressed the importance of watching political conventions during a Wednesday night appearance on "Late Show."

By Craig Berman, NBC News contributor

As the Republican National Convention was wrapping up its second night in Tampa, David Letterman turned much of his show over to Michelle Obama. Instead of discussing politics, the two mostly had a conversation about parenting.

The first lady talked about sending her daughters to sleep-away camp, counseled Letterman on getting his son involved in sports, and explained more about her efforts to improve the health of kids’ diets and ensuring that veterans were able to get jobs after leaving the army. The two also bonded over the great taste of kale chips, so the president can likely expect a big check from the ever-powerful kale lobby.

Of course, the two couldn’t avoid politics entirely. Eventually, after all the healthy diet options had been discussed, Letterman finally asked the first lady her thoughts on the RNC convention.

“I, as the wife of the guy they are running against, tend not to watch it, but I think it’s important for everyone to watch these conventions,” she said. “This is the time when you get to know the party, you get to know the platforms, and you get to understand the candidates.”

She’ll be taking on a starring role soon enough, considering her upcoming speech at the Democratic National Convention. Obama didn’t offer any details about the contents, though Letterman volunteered to send her a joke if she needed one. He also brought up the old story about Mitt Romney’s treatment of his dog on vacation, asking if the Obamas had ever thought about strapping the White House dog to the roof of the car.

“Only the best for Bo. He’s used to traveling on Air Force One,” she said.

Maher is Politically Incorrect on Leno

Jay Leno also went with a political guest, though his was more inclined to roll up his sleeves and engage in some old-fashioned trashing of the other side.

Bill Maher made no apologies for that combativeness. The ‘Real Time’ host said on the ‘Tonight Show,’ “People say they want clean campaigns. No. They want ‘The Hunger Games.’”

He offered tepid praise for Ann Romney’s convention speech but had less kind things to say about New Jersey governor Chris Christie, noting that he followed her feel-good speech with some angry rhetoric.

“Isn’t this emblematic of the Republican Party? A woman says something we all agree with that’s reasonable, and then a meathead white guy comes out and tells her to shut up,” Maher said.

Maher is not expecting much for Mitt Romney’s speech Thursday (“He has the oratorical skills of the On-Star operator”), and doesn’t expect the pick of Paul Ryan as the Republican vice presidential candidate to make a difference. “If it ever mattered, it would have mattered last time, when the world’s oldest man picked the world’s stupidest woman,” he said.

And while he’s disappointed in the Democrats, it’s safe to say that the man who gave a million dollars to the Obama campaign won’t be changing sides in 2012.

“Let’s not forget that the Republican symbol is an ‘R’ because that’s the sound a pirate makes when he robs you,” he said.

Jon Stewart took advantage of his place in Tampa to bring on one of the more engaging Republican candidates in Herman Cain, who sought and lost the nomination that Romney received.

Say this about Cain: He’s never dull. And he’s no Romney, in that he’s willing to put more of his personality out there on display.

“It’s a difference of style. My style and personality is different from Governor Romney,” Cain said. “I don’t repress my personality at all. What you see is what you get.”

Stewart also spent a lot of time tearing down the GOP in his comedy bits. Reince Priebus, Chairman of the RNC, didn’t impress Stewart with his remarks early in the convention. “If the tone you were going for was Angry Drunk Guy, you nailed it!” he said.

Nor was he impressed with the “We Built This!” theme that was evident in Tuesday’s speeches. “When was the last time we heard a catchphrase that was such a peculiar mix of braggadocio and whiny petulance?” he asked.

The screen then cut to a clip of Charlie Sheen saying his catchphrase: “Yeah, winning!”